The present invention relates to semi-transparent wood stains and, more specifically, to a method of objectively verifying properties of batches of semi-transparent wood stains.
Stains are semitransparent solutions or suspensions of coloring matter (such as dyes or pigments or both) in a vehicle, designed to color a surface by penetration without hiding it or leaving a continuous film. In contrast, paints are opaque solutions or suspensions of coloring matter in a vehicle, designed to hide or cover a surface with an opaque film.
Stains are typically manufactured in batches pursuant to a formula that specifies specific amounts of binder, colorants and other ingredients. Due to differences in the properties of ingredients from one batch to another and irregularities in processing, the color and tinting strength of a manufactured batch of a particular stain may vary from the standard color and tinting strength for the stain. Conventionally, quality control of the color of a manufactured batch of a stain is conducted by a colorist who takes a sample of the manufactured batch and applies it to a wood sample and then visually compares the stained wood sample to a piece of wood treated with the stain having the standard color and strength. If the visual inspection indicates that the color of the manufactured batch does not match the standard color of the stain, the colorist subjectively determines what changes need to be made to the manufactured batch and then the changes are made. A sample of the modified manufactured batch is then applied to the wood sample and another comparison is made. These steps are repeated until the colorist determines that the color of the manufactured batch matches the standard color of the stain. The same steps are followed to adjust the strength. As can be appreciated, such a trial-and-error method is tedious and relies upon the skill of the colorist for its effectiveness. Moreover, visual inspection typically cannot discern differences between the tinting strength of the manufactured batch and the standard tinting strength of the stain. As a result, manufactured batches could potentially be produced having unnecessarily high tinting strengths, which is uneconomical. Accordingly, there is a need in the art for an improved method of verifying and, if necessary, changing the color and tinting strength of batches of wood stains. The present invention is directed to such a method.